Sweeping benefits reforms to curb claims from people with depression and anxiety are being introduced to stop the bill rising by 52%.
Prime Minister Rishi Sunak warned the system is not working in the way it was intended.
Government spending on personal independence payments is expected to hit £32.8bn by 2027/28.
Reforms to PIP could include stopping regular cash payments, and instead offering claimants one-off grants for things like home adaptations.
Mr Sunak said: “It’s clear that our disability benefits system isn’t working in the way it was intended, and we’re determined to reform it to ensure it’s sustainable for the future, so we can continue delivering support to those who genuinely need it most.”
Ministers say the reforms will mean the disability benefit system is targeted at those most in need.
The proposals, which have gone out to consultation, include shifting away from a fixed cash benefit system towards tailored support.
More than 2.6 million people of working age now receive PIP with monthly new claims almost doubling since 2019.
The payment, a maximum of £184.30 a week, was introduced a decade ago to replace Disability Living Allowance to help with extra living costs caused by long-term disabilities or ill health.
Work and Pensions Secretary Mel Stride said benefits should not be the first option for people with milder mental health conditions, insisting the system should not be paying people to deal with the “ordinary difficulties of life”.
Ceri Smith, Head of Policy at the MS Society, on behalf of the Disability Benefits Consortium, said: “This consultation is cynical and cruel, unjustly targeting disabled people, including those with MS. MS can be debilitating, exhausting and unpredictable, and PIP is a lifeline to many, helping to fund the extra costs of being disabled.
“In many cases, it can actually help people stay in work and maintain their independence for longer.
“If the government truly wants a ‘stronger, healthier and fairer society’, they should start by addressing NHS waiting lists and fixing social care. Instead, this approach will punish disabled people and push even more into poverty.”
